COMPARISON OF PHOSPHROUS, ORGANIC CARBON, CARBONATE, AND IRON BURIAL IN CENOMANIAN-TURONIAN STRATA OF THE WESTERN INTERIOR BASIN
It has been suggested by paleoceanographers that Cretaceous oceans were oligotrophic and that ancient epeiric seas would have acted as extensions of the surface ocean during sea level highstands. Under such conditions, would additions of regenerated P to the background fluvial input have significant effects on production? How would such changes compare to the influence of oxygen minimum zone waters advected into the basin? In this study trends in the concentration and accumulation rate of P in strata of the Western Interior are compared with similar data for carbonate, organic carbon, and iron. Accumulation rate calculations are based on recent development of an orbital time scale for the study interval. An onshore-offshore data transect allows the influence of fluvial P sources to be evaluated, and a stratigraphic data set across the Cenomanian-Turonian boundary reveals the record of changes in P burial associated with major shifts in water masses and benthic redox conditions (i.e., Oceanic Anoxic Event II). The results allow a preliminary model summarizing changes in the Western Interior P-cycle under different oceanographic and biogeochemical scenarios to be proposed.